imec, the Belgian nanoelectronics research institute, sits upstream of the entire foundry industry: it originates device concepts - forksheet, CFET, and much of the GAA roadmap - that TSMC, Samsung, and Intel later commercialize. It also patents them, and its late-2025 grant on multiport memory cells with stacked active layers is a case of the originator holding the IP.
US12424276B2, "Multiport memory cells including stacked active layers" (issued 2025-09-23, assignee IMEC VZW), is classified in G11C 11/419 (SRAM access) with H10B 10/12 (SRAM structures), H10B 80/00 (assemblies of memory devices), and H01L 23/5226. The claim covers a multiport cell - one accessible through multiple ports at once - built using stacked active layers rather than a single planar device layer.
Construe the two-part limitation: multiport plus stacked layers. Multiport cells (dual-port, two-read-one-write) are standard in register files. The novelty is realizing the multiport function using vertically stacked active device layers, which packs the extra access devices into less footprint. The claim turns on that stacked-layer realization of the multiport function.
The design-around space is the port implementation. A competitor building a multiport cell with planar (side-by-side) devices, or a different vertical arrangement, reaches multiport functionality outside a claim tied to stacked active layers. As 3D device stacking matures, though, the stacked approach becomes more attractive and the claim more relevant.
imec's commercialization model is distinctive: it does not manufacture, but its members - the major foundries and IDMs that fund its programs - get licensed access, and its patents become part of the shared roadmap IP. A claim like this often shows up later, lightly modified, in a foundry's product, with imec's priority date underneath.
For a portfolio analyst, watching imec's grants is a leading indicator: its device-structure claims foreshadow what the foundries will ship in two to four years. Stacked-active-layer multiport cells signal that 3D stacking is reaching even the multiport-memory corner of the design, and imec's IP will sit beneath whoever commercializes it.